1. Field of the Invention
The invention relates to a seatbelt use indicating apparatus and method and, more particularly, to a seatbelt use indicating apparatus that has a warning lamp that prompts an occupant to use a seatbelt device.
2. Description of the Related Art
Vehicles equipped with seatbelt devices have a seatbelt warning lamp for warning of non-use of the seatbelt.
Such a seatbelt warning lamp is provided with an occupant detection sensor and a buckle switch that form a circuit. If an occupant is detected via the occupant detection sensor but the seatbelt is not worn (the buckle switch is off), the warning lamp flickers.
For example, Japanese Patent Application Laid-Open Publication No. 11-348729 proposes an apparatus (first related-art technology) in which if a human body sensor for detecting the presence/absence of a human body detects a human body and a seatbelt use detection switch provided in a buckle portion for detecting the fastening of a seatbelt is off, a control portion sends a signal to a warning portion. This arrangement allows appropriate execution of occupant detection and appropriate execution of diagnosis of the occupant detection switch.
Japanese Patent Application Laid-Open Publication No. 2002-260119 proposes a technology (second related-art technology) in which it is determined whether a seatbelt device is appropriately worn and used on the basis of results of detection by various sensors or the like; for example, it is detected whether the shoulder anchor of the seatbelt device is set so that the belt extends on an occupant's shoulder through the use of an image processing technique or the like, and if it is determined that the seatbelt device is appropriately used, a green or blue-color indication is produced or a voice guidance is output.
However, in the first related-art technology, when an occupant fastens the seatbelt device, the warning lamp turns off. The warning lamp is also off when there is no occupant. Therefore, if the warning lamp fails to turn on, it is not easy to recognize whether the seatbelt device in use or not in use.
Furthermore, the first and second related-art technologies have a problem of increased costs due to the employment of an occupant detection sensor, an image processing technique or the like in order to determine the presence/absence of an occupant.